Associate brightness/contrast with alignments (per-alignment B/C)

[dustenhubbard]

Problem

Brightness/contrast is not tied to individual alignments. This is tied to the autoseg workflow, assigning to Vijay.

Proposed

Let each alignment carry its own brightness/contrast.

Notes

KH's request (verbatim): "Brightness / contrast - are they associated with alignments? They should be, allow unique brightness/contrast for each alignment."
Today they are separate: B/C lives per section in section.bc_profiles keyed by the series-level series.bc_profile, while transforms live per section in section.tforms keyed by series.alignment. changeAlignment() (gui/main/field_widget_4_data.py) and changeBCProfile() (gui/main/field_widget_7_view.py) are independent, so changing the alignment does not change the B/C profile. The two are already parallel per-section keyed dicts, so associating them (e.g. switching the B/C profile alongside the alignment) is a natural fit. A named B/C-profile feature partly covers "unique B/C" but is not linked to alignments.

[quasiTriestino]

Multiple brightness and contrast profiles are stored in the jser. For the time being, name the brightness contrast profile the same name as the alignment. Will consider adding to standard operating procedure to help menu.